The nucleolus is a nuclear compartment that plays an important role in ribosome biogenesis. Some structural features and epigenetic patterns are shared between nucleolar and non-nucleolar compartments. For example, the location of transcriptionally active mRNA on extended chromatin loop species is similar to that observed for transcriptionally active ribosomal DNA (rDNA) genes on so-called Christmas tree branches. Similarly, nucleolus organizer region-bearing chromosomes located a distance from the nucleolus extend chromatin fibers into the nucleolar compartment. Specific epigenetic events, such as histone acetylation and methylation and DNA methylation, also regulate transcription of both rRNA- and mRNA-encoding loci. Here, we review the epigenetic mechanisms and structural features that regulate transcription of ribosomal and mRNA genes. We focus on similarities in epigenetic and structural regulation of chromatin in nucleoli and the surrounding non-nucleolar region and discuss the role of proteins, such as heterochromatin protein 1, fibrillarin, nucleolin, and upstream binding factor, in rRNA synthesis and processing.

• MeSH
• buněčné jadérko genetika   metabolismus   ultrastruktura   MeSH
• chromatin genetika   ultrastruktura   MeSH
• epigeneze genetická * MeSH
• genetická transkripce MeSH
• geny rRNA MeSH
• histony metabolismus   MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• ribozomální DNA genetika   MeSH
• ribozomy genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• srovnávací studie MeSH
• Názvy látek
• chromatin MeSH
• histony MeSH
• messenger RNA MeSH
• ribozomální DNA MeSH

Mammalian heterochromatin protein 1 (HP1alpha, HP1beta, HP1gamma subtypes) and transcriptional intermediary factor TIF1beta play an important role in the regulation of chromatin structure and function. Here, we investigated the nuclear arrangement of these proteins during differentiation of embryonal carcinoma P19 cells into primitive endoderm and into the neural pathway. Additionally, the differentiation potential of trichostatin A (TSA) and 5-deoxyazacytidine (5-dAzaC) was studied. In 70% of the cells from the neural pathway and in 20% of TSA-stimulated cells, HP1alpha and HP1beta co-localized and associated with chromocentres (clusters of centromeres), which correlated with clustering of TIF1beta at these heterochromatic regions. The cell types that we studied were also characterized by a pronounced focal distribution of HP1gamma. The above-mentioned nuclear patterns of HP1 and TIF1beta proteins were completely different from the nuclear patterns observed in the remaining cell types investigated, in which HP1alpha was associated with chromocentres while HP1beta and HP1gamma were largely localized in distinct nuclear regions. Moreover, a dispersed nuclear distribution of TIF1beta was observed. Our findings showed that the nuclear arrangement of HP1 subtypes and TIF1beta is differentiation specific, and seems to be more important than changes in the levels of these proteins, which were relatively stable during all the induced differentiation processes.

• MeSH
• azacytidin analogy a deriváty   farmakologie   MeSH
• buněčná diferenciace účinky léků   fyziologie   MeSH
• buněčné jádro metabolismus   MeSH
• centromera metabolismus   MeSH
• chromozomální proteiny, nehistonové genetika   metabolismus   MeSH
• decitabin MeSH
• homolog proteinu s chromoboxem 5 MeSH
• imunohistochemie MeSH
• inhibitory enzymů farmakologie   MeSH
• inhibitory histondeacetylas MeSH
• jaderné proteiny metabolismus   MeSH
• konfokální mikroskopie MeSH
• kyseliny hydroxamové farmakologie   MeSH
• metylace DNA účinky léků   MeSH
• nádorové buněčné linie MeSH
• podjednotky proteinů genetika   metabolismus   MeSH
• rekombinantní fúzní proteiny genetika   metabolismus   MeSH
• signální transdukce účinky léků   MeSH
• transkripční faktory metabolismus   MeSH
• western blotting MeSH
• zelené fluorescenční proteiny genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• azacytidin MeSH
• chromozomální proteiny, nehistonové MeSH
• decitabin MeSH
• homolog proteinu s chromoboxem 5 MeSH
• inhibitory enzymů MeSH
• inhibitory histondeacetylas MeSH
• jaderné proteiny MeSH
• kyseliny hydroxamové MeSH
• podjednotky proteinů MeSH
• rekombinantní fúzní proteiny MeSH
• transcriptional intermediary factor 1 MeSH Prohlížeč
• transkripční faktory MeSH
• trichostatin A MeSH Prohlížeč
• zelené fluorescenční proteiny MeSH